Redis test: include bug report on crash.

Due to a change in the format of the bug report in case of crash of
failed assertion the test suite was no longer able to properly log it.
Instead just a protocol error was logged by the Redis TCL client that
provided no clue about the actual problem.

This commit resolves the issue by logging everything from the first line
of the log including the string REDIS BUG REPORT, till the end of the
file.

tests/support/util.tcl

@@ -30,12 +30,16 @@ proc zlistAlikeSort {a b} {
 proc warnings_from_file {filename} {
     set lines [split [exec cat $filename] "\n"]
     set matched 0
+    set logall 0
     set result {}
     foreach line $lines {
+        if {[string match {*REDIS BUG REPORT START*} $line]} {
+            set logall 1
+        }
         if {[regexp {^\[\d+\]\s+\d+\s+\w+\s+\d{2}:\d{2}:\d{2} \#} $line]} {
             set matched 1
         }
-        if {$matched} {
+        if {$logall || $matched} {
             lappend result $line
         }
     }